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SubjectRe: KASAN: slab-out-of-bounds Read in vhci_hub_control
On Tue, Oct 2, 2018 at 6:04 PM, Shuah Khan <> wrote:
> On 09/04/2018 12:52 PM, syzbot wrote:
>> Hello,
>> syzbot found the following crash on:
>> HEAD commit: 420f51f4ab6b Merge tag 'arm64-fixes' of git://git.kernel.o..
>> git tree: upstream
>> console output:
>> kernel config:
>> dashboard link:
>> compiler: gcc (GCC) 8.0.1 20180413 (experimental)
>> syz repro:
>> C reproducer:
> C producer doesn't reproduce the problem on 4.19-rc5. Does this C producer
> depend on state of the machine? i.e what is the status of vhci_hcd - are
> there any devices attached?

Hi Shuah,

syzbot always runs tests reproducers on a clean machine. There is some
state are running a Debian wheezy init, but no test/fuzz/stress
workload is run before the reproducer.
syzbot also uses VMs, so there are no real devices attached. And it's
GCE VMs (not qemu), and I think GCE does not even emulate any USB

An obvious thing to try would be to use the exact commit and config
syzbot gave (rather than 4.19-rc5).
You can also take the image syzbot uses here:

> I can see the problem looking at the code and fix is easy. However, I would
> like be able to reproduce it and verify the fix works. Also this would be a
> good regression for the driver I could consider adding to selftests.

syzbot can test fixes for bugs with reproducers:
So it can test your fix. But this obviously won't help with a test.

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